SWI/SNF chromatin remodeling complex is required for initiation of sex-dependent differentiation in mouse germline

AbstractSexual reproduction involves the creation of sex-dependent gametes, oocytes and sperm. In mammals, sexually dimorphic differentiation commences in the primordial germ cells (PGCs) in embryonic gonads; PGCs in ovaries and testes differentiate into meiotic primary oocytes and mitotically quiescent prospermatogonia, respectively. Here, we show that the transition from PGCs to sex-specific germ cells was abrogated in conditional knockout mice carrying a null mutation of Smarcb1 (also known as Snf5) gene, which encodes a core subunit of the SWI/SNF chromatin remodeling complex. In female mutant mice, failure to upregulate meiosis-related genes resulted in impaired meiotic entry and progression, including defects in synapsis formation and DNA double strand break repair. Mutant male mice exhibited delayed mitotic arrest and DNA hypomethylation in retrotransposons and imprinted genes, resulting from aberrant expression of genes related to growth and de novo DNA methylation. Collectively, our results demonstrate that the SWI/SNF complex is required for transcriptional reprogramming in the initiation of sex-dependent differentiation of germ cells.

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Effects of ten–eleven translocation 1 (Tet1) on DNA methylation and gene expression in chicken primordial germ cells

Reproduction Fertility and Development ◽

10.1071/rd18145 ◽

2019 ◽

Vol 31 (3) ◽

pp. 509 ◽

Cited By ~ 1

Author(s):

Minli Yu ◽

Dongfeng Li ◽

Wanyan Cao ◽

Xiaolu Chen ◽

Wenxing Du

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Germ Cells ◽

Dna Methyltransferase ◽

Primordial Germ Cells ◽

Dna Demethylation ◽

Caveolin 1 ◽

Expression Of Genes ◽

Deleted In Azoospermia

Ten–eleven translocation 1 (Tet1) is involved in DNA demethylation in primordial germ cells (PGCs); however, the precise regulatory mechanism remains unclear. In the present study the dynamics of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in developing PGCs and the role of Tet1 in PGC demethylation were analysed. Results show that 5mC levels dropped significantly after embryonic Day 4 (E4) and 5hmC levels increased reaching a peak at E5–E5.5. Interestingly, TET1 protein was highly expressed during E5 to E5.5, which showed a consistent trend with 5hmC. The expression of pluripotency-associated genes (Nanog, PouV and SRY-box 2 (Sox2)) and germ cell-specific genes (caveolin 1 (Cav1), piwi-like RNA-mediated gene silencing 1 (Piwi1) and deleted in azoospermia-like (Dazl)) was upregulated after E5, whereas the expression of genes from the DNA methyltransferase family was decreased. Moreover, the Dazl gene was highly methylated in early PGCs and then gradually hypomethylated. Knockdown of Tet1 showed impaired survival and proliferation of PGCs, as well as increased 5mC levels and reduced 5hmC levels. Further analysis showed that knockdown of Tet1 led to elevated DNA methylation levels of Dazl and downregulated gene expression including Dazl. Thus, this study reveals the dynamic epigenetic reprogramming of chicken PGCs invivo and the molecular mechanism of Tet1 in regulating genomic DNA demethylation and hypomethylation of Dazl during PGC development.

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A Drosophila toolkit for defining gene function in spermatogenesis

Reproduction ◽

10.1530/rep-16-0347 ◽

2017 ◽

Vol 153 (4) ◽

pp. R121-R132 ◽

Cited By ~ 8

Author(s):

N A Siddall ◽

G R Hime

Keyword(s):

Germ Cells ◽

Gene Function ◽

Primordial Germ Cells ◽

Rapid Assessment ◽

Model Organism ◽

Time Frame ◽

Individual Organism ◽

Expression Of Genes ◽

X Irradiation ◽

Human Spermatogenesis

Expression profiling and genomic sequencing methods enable the accumulation of vast quantities of data that relate to the expression of genes during the maturation of male germ cells from primordial germ cells to spermatozoa and potential mutations that underlie male infertility. However, the determination of gene function in specific aspects of spermatogenesis or linking abnormal gene function with infertility remain rate limiting, as even in an era of CRISPR analysis of gene function in mammalian models, this still requires considerable resources and time. Comparative developmental biology studies have shown the remarkable conservation of spermatogenic developmental processes from insects to vertebrates and provide an avenue of rapid assessment of gene function to inform the potential roles of specific genes in rodent and human spermatogenesis. The vinegar fly, Drosophila melanogaster, has been used as a model organism for developmental genetic studies for over one hundred years, and research with this organism produced seminal findings such as the association of genes with chromosomes, the chromosomal basis for sexual identity, the mutagenic properties of X-irradiation and the isolation of the first tumour suppressor mutations. Drosophila researchers have developed an impressive array of sophisticated genetic techniques for analysis of gene function and genetic interactions. This review focuses on how these techniques can be utilised to study spermatogenesis in an organism with a generation time of 9 days and the capacity to introduce multiple mutant alleles into an individual organism in a relatively short time frame.

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INO80 requires a polycomb subunit to regulate the establishment of poised chromatin in murine spermatocytes

Development ◽

10.1242/dev.200089 ◽

2022 ◽

Vol 149 (1) ◽

Author(s):

Prabuddha Chakraborty ◽

Terry Magnuson

Keyword(s):

Chromatin Remodeling ◽

Binding Sites ◽

Strand Break ◽

Rna Seq ◽

Genome Wide Analysis ◽

The Core ◽

Chromatin Remodeling Complex ◽

Genome Wide ◽

Dna Double Strand Break ◽

Transcription Program

ABSTRACT INO80 is the catalytic subunit of the INO80-chromatin remodeling complex that is involved in DNA replication, repair and transcription regulation. Ino80 deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes due to incomplete synapsis and aberrant DNA double-strand break repair, which leads to apoptosis. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WT spermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Furthermore, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment and, in turn, showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Furthermore, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.

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17β-Trenbolone binds to androgen receptor, decreases number of primordial germ cells, modulates expression of genes related to sexual differentiation, and affects sexual differentiation in zebrafish (Danio rerio)

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.150959 ◽

2021 ◽

pp. 150959

Author(s):

Hua Tian ◽

Rui Liu ◽

Suqiu Zhang ◽

Shuhui Wei ◽

Wei Wang ◽

...

Keyword(s):

Androgen Receptor ◽

Germ Cells ◽

Danio Rerio ◽

Sexual Differentiation ◽

Primordial Germ Cells ◽

Expression Of Genes

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Stage-specific transcriptomes and DNA methylomes indicate an early and transient loss of transposon control in Arabidopsis shoot stem cells

10.1101/430447 ◽

2018 ◽

Cited By ~ 3

Author(s):

Ruben Gutzat ◽

Klaus Rembart ◽

Thomas Nussbaumer ◽

Rahul Pisupati ◽

Falko Hofmann ◽

...

Keyword(s):

Stem Cells ◽

Germ Cells ◽

Early Stage ◽

Primordial Germ Cells ◽

Postembryonic Development ◽

Specific Gene ◽

Germline Development ◽

Expression Of Genes ◽

Deep Embedding ◽

Cell Expression

In contrast to animals, postembryonic development in plants is modular, and aerial organs originate from stem cells in the center of the shoot apical meristem (SAM) throughout life. Descendants of SAM stem cells in the subepidermal layer (L2) give also rise to male and female gametes (reviewed in 1) and are therefore considered primordial germ cells. In these cells, transmission of somatic mutations including virus and TE insertions must be avoided. Despite their essential role for plant development and intergenerational continuity, no comprehensive molecular analysis of SAM stem cells exists, due to their low number, deep embedding among non-stem cells, and difficult isolation. Here we present a comprehensive analysis of stage-specific gene expression and DNA methylation dynamics in Arabidopsis SAM stem cells. Stem cell expression signatures are mostly defined by development, but we also identified a core set of differentially expressed stemness genes. Surprisingly, vegetative SAM stem cells showed increased expression of transposable elements (TEs) relative to surrounding cells, despite high expression of genes connected to epigenetic silencing. We also find increasing methylation at CHG and a drop in CHH methylation at TEs before stem cells enter the reproductive lineage, indicating an onset of epigenetic reprogramming at an early stage. Transiently elevated TE expression is reminiscent of that in animal primordial germ cells (PGCs) 2 and demonstrates commonality of transposon biology. Our results connect SAM stem cells with germline development and transposon evolution and will allow future experiments to determine the degree of epigenetic heritability between generations.

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Chromatin remodeler Brahma safeguards canalization in cardiac mesoderm differentiation

10.1101/2020.06.03.132654 ◽

2020 ◽

Cited By ~ 1

Author(s):

Swetansu K. Hota ◽

Andrew P. Blair ◽

Kavitha S. Rao ◽

Kevin So ◽

Aaron M. Blotnick ◽

...

Keyword(s):

Cell Fate ◽

Chromatin Remodeling ◽

De Novo ◽

Embryonic Stem ◽

Mesoderm Induction ◽

Chromatin Remodeling Complex ◽

Atpase Gene ◽

Neurogenic Factor ◽

Well Differentiated ◽

Cardiac Mesoderm

SUMMARYDifferentiation proceeds along a continuum of increasingly fate-restricted intermediates, referred to as canalization1–4. Canalization is essential for stabilizing cell fate, but the mechanisms underlying robust canalization are unclear. Here we show that deletion of the BRG1/BRM-associated factor (BAF) chromatin remodeling complex ATPase gene Brm (encoding Brahma) results in a radical identity switch during directed cardiogenesis of mouse embryonic stem cells (ESCs). Despite establishment of well-differentiated precardiac mesoderm, Brm-null cells subsequently shifted identities, predominantly becoming neural precursors, violating germ layer assignment. Trajectory inference showed sudden acquisition of non-mesodermal identity in Brm-null cells, consistent with a new transition state inducing a fate switch referred to as a saddle-node bifurcation3,4. Mechanistically, loss of Brm prevented de novo accessibility of cardiac enhancers while increasing expression of the neurogenic factor POU3F1 and preventing expression of the neural suppressor REST. Brm mutant identity switch was overcome by increasing BMP4 levels during mesoderm induction, repressing Pou3f1 and re-establishing a cardiogenic chromatin landscape. Our results reveal BRM as a compensable safeguard for fidelity of mesoderm chromatin states, and support a model in which developmental canalization is not a rigid irreversible path, but a highly plastic trajectory that must be safeguarded, with implications in development and disease.

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A Reporter Mouse for In Vivo Detection of DNA Damage in Embryonic Germ Cells

10.1101/2020.01.29.925487 ◽

2020 ◽

Author(s):

Jordana C. Bloom ◽

John C. Schimenti

Keyword(s):

Dna Damage ◽

Germ Cells ◽

Primordial Germ Cells ◽

Strand Break ◽

Dependent Manner ◽

Dna Double Strand Breaks ◽

Specific Expression ◽

Exogenous Dna ◽

Embryonic Germ Cells

AbstractMaintaining genome integrity in the germline is essential for survival and propagation of a species. In both mouse and human, germ cells originate during fetal development and are hypersensitive to both endogenous and exogenous DNA damaging agents. Currently, mechanistic understanding of how primordial germ cells respond to DNA damage is limited in part by the tools available to study these cells. We developed a mouse transgenic reporter strain expressing a 53BP1-mCherry fusion protein under the control of the Oct4ΔPE embryonic germ cell-specific promoter. This reporter binds sites of DNA double strand breaks (DSBs) on chromatin, forming foci. Using ionizing radiation as a DNA double strand break-inducing agent, we show that the transgenic reporter expresses specifically in the embryonic germ cells of both sexes and forms DNA damage induced foci in both a dose- and time-dependent manner. The dynamic time-sensitive and dose-sensitive DNA damage detection ability of this transgenic reporter, in combination with its specific expression in embryonic germ cells, makes it a versatile and valuable tool for increasing our understanding of DNA damage responses in these unique cells.

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Regulation of Telomere Structure and Functions by Subunits of the INO80 Chromatin Remodeling Complex

Molecular and Cellular Biology ◽

10.1128/mcb.00418-07 ◽

2007 ◽

Vol 27 (16) ◽

pp. 5639-5649 ◽

Cited By ~ 45

Author(s):

Eun Young Yu ◽

Olga Steinberg-Neifach ◽

Alain T. Dandjinou ◽

Frances Kang ◽

Ashby J. Morrison ◽

...

Keyword(s):

Chromatin Remodeling ◽

Position Effect ◽

Strand Break ◽

Telomere Maintenance ◽

Regulation Of Transcription ◽

Chromatin Remodeling Complex ◽

Dna Double Strand Break ◽

Preferential Localization ◽

Chromatin Remodeling Complexes ◽

Tetratricopeptide Repeat Domain

ABSTRACT ATP-dependent chromatin remodeling complexes have been implicated in the regulation of transcription, replication, and more recently DNA double-strand break repair. Here we report that the Ies3p subunit of the Saccharomyces cerevisiae INO80 chromatin remodeling complex interacts with a conserved tetratricopeptide repeat domain of the telomerase protein Est1p. Deletion of IES3 and some other subunits of the complex induced telomere elongation and altered telomere position effect. In telomerase-negative mutants, loss of Ies3p delayed the emergence of recombinational survivors and stimulated the formation of extrachromosomal telomeric circles in survivors. Deletion of IES3 also resulted in heightened levels of telomere-telomere fusions in telomerase-deficient strains. In addition, a delay in survivor formation was observed in an Arp8p-deficient mutant. Because Arp8p is required for the chromatin remodeling activity of the INO80 complex, the complex may promote recombinational telomere maintenance by altering chromatin structure. Consistent with this notion, we observed preferential localization of multiple subunits of the INO80 complex to telomeres. Our results reveal novel functions for a subunit of the telomerase complex and the INO80 chromatin remodeling complex.

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Derepression of INO1 Transcription Requires Cooperation between the Ino2p-Ino4p Heterodimer and Cbf1p and Recruitment of the ISW2 Chromatin-Remodeling Complex

Eukaryotic Cell ◽

10.1128/ec.00144-10 ◽

2010 ◽

Vol 9 (12) ◽

pp. 1845-1855 ◽

Cited By ~ 13

Author(s):

Ameet Shetty ◽

John M. Lopes

Keyword(s):

Chromatin Remodeling ◽

Binding Sites ◽

De Novo ◽

Bhlh Protein ◽

Promoter Element ◽

Content Type ◽

Reading Frame ◽

Helix Loop Helix ◽

Chromatin Remodeling Complex ◽

Binding Factor

ABSTRACT The Saccharomyces cerevisiae INO1 gene encodes the structural enzyme inositol-3-phosphate synthase for the synthesis de novo of inositol and inositol-containing phospholipids. The transcription of INO1 is completely derepressed in the absence of inositol and choline (I− C−). Derepression requires the binding of the Ino2p-Ino4p basic helix-loop-helix (bHLH) heterodimer to the UAS INO promoter element. We report here the requirement of a third bHLH protein, centromere-binding factor 1 (Cbf1p), for the complete derepression of INO1 transcription. We found that Cbf1p regulates INO1 transcription by binding to sites distal to the INO1 promoter and encompassing the upstream SNA3 open reading frame (ORF) and promoter. The binding of Cbf1p requires Ino2p-Ino4p binding to the UAS INO sites in the INO1 promoter and vice versa, suggesting a cooperative mechanism. Furthermore, Cbf1p binding to the upstream sites was required for the binding of the ISW2 chromatin-remodeling complex to the Ino2p-Ino4p-binding sites on the INO1 promoter. Consistent with this, ISW2 was also required for the complete derepression of INO1 transcription.

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